This happened to me! but I have three characters instead of one. Two of my char. were unplayable. If I tapped on the top slot, it would go into a new character with the deafault PC look, which is impossible to get on mobile due to limited colour selection. It had no name, like in the screenshot, but on multiplayer my name was always changing. It has ranged from ITEMNAME[262] to Copper coin (54).
My middle slot was what used to be my top slot: I.e they had moved down a notch.
My last character got deleted altogether; tapping on it would lead to the character create screen.
I fixed it by deleting the first character, moving everything up a notch. My only character that was available before I tried to fix it got deleted completely, because (I think) that the trash can didn't move down with the character. Confusing stuff.
However, the two characters that weren't availible came back fine (I still have them). The last slot (the one with the create character on it) stayed the same, and so I sadly created another character, knowing that my best Mage character (he had an inferno fork, Shadowbeam staff, spectre staff, bat sceptor...) was gone permanently.
Sorry if this bored you, but I'm just trying to put exactly what I did to (sort of) fix it. Hope this helped, but; learn from my mistake, and put all of you characters items in a chest in a secure world. (Cloud world has never failed me) before attempting to fix it.